Leg 4: March 15, 2012

Day 2: The blob that ate the seafloor

While transecting with the remotely operated vehicle along a smooth ridge pushed up from the seafloor at a depth of 2,700 meters (8,858 feet) we came across a pulsing yellow blob surrounding a hole in the mud. A creature straight out of a 1950s science fiction movie?

This was not one big creature, but rather an assemblage of tiny creatures—bacteria that live off the chemicals rising up from the seafloor. The pressure of the hot water emanating from the crack in the seafloor pushed against the soft mass of bacteria, making it appear to have its own heartbeat.

This soft blob of bacteria was pulsing with the flow of the fluid from below. The color indicates these microbes are feeding on sulfur, and the fact that no giant clams or tubeworms were seen in the area suggests that this is a fairly new fluid flow, as older vent sites are usually teeming with such life.

This soft blob of bacteria was pulsing with the flow of the fluid from below. The color indicates these microbes are feeding on sulfur, and the fact that no giant clams or tubeworms were seen in the area suggests that this is a fairly new fluid flow, as older vent sites are usually teeming with such life.

Today’s exploration was on a small mound in the axis of a large valley on the seafloor. Such mounds usually indicate some kind of chemical venting from the seafloor and therefore are targets for the Brewer team’s investigations. The geological forces under the Gulf of California are actively pushing the Baja California peninsula away from mainland Mexico, and creating cracks in the seafloor allowing fluids and gases to escape from below. So while we expect to find some sea life that thrive on sulfur, methane, or other chemically-laden fluids, we don’t always know just what we will find in any particular area.

A group of white sponges were found living on a small ridge on top of the mound in the middle of the seafloor.

A group of white sponges were found living on a small ridge on top of the mound in the middle of the seafloor.

Though today’s dive presented several technical challenges that cut the day shorter than planned, the team did manage to take a few profiles of the chemistry of the pore water in the seafloor and collected some sediment cores and water samples.

At the end of the day, Chief Scientist Peter Brewer, center, meets with his team, Peter Walz, left, and Ed Peltzer, to discuss how to improve the performance of their newest tool, the tripod, designed to precisely guide the laser probe into the seafloor.

At the end of the day, Chief Scientist Peter Brewer, center, meets with his team, Peter Walz, left, and Ed Peltzer, to discuss how to improve the performance of their newest tool, the tripod, designed to precisely guide the laser probe into the seafloor.


Professor Martín Hernández Ayón and his student Gaby Cervantes process a sample of sediments collected from the deep seafloor. They will analyze the samples to determine what heavy metals are present in the seafloor.

Professor Martín Hernández Ayón and his student Gaby Cervantes process a sample of sediments collected from the deep seafloor. They will analyze the samples to determine what heavy metals are present in the seafloor.


While the Brewer team was working with the ROV Doc Ricketts today, the MBARI AUV mapping team was just a few kilometers away mapping another section of the seafloor. By the morning we hope to receive the new detailed maps from this latest survey, so that we can carefully locate our next dive in a place of scientific interest to this team of ocean chemists.

—Nancy Barr

MBARI's mapping AUV, the

Equipment

Gulf of California 2012 Expedition